Device and method for controlling in-vivo pressure

ABSTRACT

A differential pressure regulating device is provided for controlling in-vivo pressure in a body, and in particularly in a heart. The device may include a shunt being positioned between two or more lumens in a body, to enable fluids to flow between the lumens, and an adjustable flow regulation mechanism being configured to selectively cover an opening of the shunt, to regulate the flow of fluid through the shunt in relation to a pressure difference between the body lumens. In some embodiments a control mechanism coupled to the adjustable flow regulation mechanism may be provided, to remotely activate the adjustable flow regulation mechanism.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 35 U.S.C. §120 of U.S. patentapplication Ser. No. 10/597,666, filed Jun. 20, 2007 and entitled“Device and Method for Controlling In-Vivo Pressure,” which is a U.S.national stage filing under 35 U.S.C. §371 of International PatentApplication No. PCT/IL2005/000131, filed Feb. 3, 2005, which claims thebenefit of U.S. Provisional Patent Application No. 60/541,267, filedFeb. 3, 2004, and U.S. Provisional Patent Application No. 60/573,378,filed May 24, 2004, the entire contents of each of which areincorporated by reference herein.

This application is also a continuation-in-part under 35 U.S.C. §120 ofU.S. patent application Ser. No. 09/839,643, filed Apr. 20, 2001 andentitled “Methods and Apparatus for Reducing Localized CirculatorySystem Pressure,” the entire contents of which are incorporated byreference herein.

FIELD OF THE INVENTION

The present invention relates to devices and methods for reducing orregulating pressure within a circulatory system, and in particular toregulate blood pressure in a heart.

BACKGROUND OF THE INVENTION

CHF is recognized as one of the most common causes of hospitalizationand mortality in Western society, and has a great impact on the qualityof life. CHF is a disorder characterized by low systemic perfusion andinefficient cardiac function. CHF causes may include myocardial insultdue to ischemia, cardiomyopathy and other processes. Pathophysiologicmechanisms that are directly associated with CHF include reduced cardiacoutput, increase in cardiac filling pressures, and fluid accumulation,which may lead to, for example, pulmonar congestion and dyspnea.Impairment of systolic function may result in poor left ventricularcontraction and reduced cardiac output, which may generate clinicalsymptoms including effort intolerance, dyspnea, reduced longevity, edema(lung or peripheral) and pain. A patient with systolic dysfunction mayusually have a larger left ventricle because of phenomena called cardiacremodeling aimed to maintain adequate stroke-volume. Thispathophisiologic mechanism is associated with increased atrial pressureand left ventricular filling pressure. With abnormal diastolic function,the left ventricle may be stiff and markedly less compliant partlybecause of abnormal relaxation leading to inadequate cardiac filling atnormal pressures. Maintenance of adequate cardiac filling at higherfilling pressures may be needed to maintain cardiac output. Thismandatory rise of filling pressure to maintain cardiac filling andoutput may lead to pulmonary venous hypertension and lung edema.

Presently available treatments for CHF fall into three generallycategories: (1) pharmacological, e.g., diuretics; (2) assist systems,e.g., pumps; and (3) surgical treatments. With respect topharmacological treatments, vasodilators have been used to reduce theworkload of the heart by reducing systemic vascular resistance anddiuretics to prevent fluid accumulation and edema formation, and reducecardiac filling pressure.

Assist devices used to treat CHF may include, for example, mechanicalpumps. Mechanical pumps reduce the load on the heart by performing allor part of the pumping function normally done by the heart. Currently,mechanical pumps are used, for example, to sustain the patient while adonor heart for transplantation becomes available for the patient. Thereare also a number of pacing devices used to treat CHF.Resysnchronization pacemakers have also been used to treat CHF. Finally,there are at least three extremely invasive and complex surgicalprocedures for treatment of heart failure: 1) heart transplant; 2)dynamic cardiomyoplasty; and 3) the Batista partial leftventriculectomy.

In extreme acute situations, temporary assist devices and intraaorticballoons may be helpful. Cardiac transplantation and chronic leftventricular assist device (LVAD) implants may often be used as lastresort. However, all the assist devices currently used are intended toimprove pumping capacity of the heart and increase cardiac output tolevels compatible with normal life, reducing filling pressures and/orpreventing edema formation. Finally, cardiac transplantation may be usedto treat extreme cardiac dysfunction cases, however this procedure ishighly invasive and is limited by the availability of donor hearts. Themechanical devices may allow propulsion of significant amount of blood(liters/min) and this is also their main limitation. The need for powersupply, relatively large pumps and possibility of hemolysis andinfection are all of concern.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with features and advantages thereof, may best be understood byreference to the following detailed description when read with theaccompanied drawings in which:

FIG. 1A is a schematic illustration of a Differential PressureRegulation Device (DPRD), in accordance with an exemplary embodiment ofthe invention;

FIGS. 1B-1I are schematic illustrations of additional embodiments ofDifferential Pressure Regulation Devices (DPRD), in accordance with someembodiments of the invention;

FIG. 1J is a chart describing an example of a pressure curve related tothe relationship between the change in pressure difference between twolumens, the flow through the flow control mechanism and the orificearea, in accordance with an exemplary embodiment of the presentinvention;

FIGS. 2A and 2B are schematic illustrations of a cross-section view anda side view, respectively, of an adjustable shunt, tube or otherstructure in accordance with an exemplary embodiment of the invention;

FIG. 3 is a schematic illustration of a shunt in accordance with anotherexemplary embodiment of the invention;

FIG. 4 is a schematic illustration of a shunt including a FlowRegulation Mechanism (FRM) in accordance with an exemplary embodiment ofthe invention;

FIG. 5 is a schematic illustration of the shunt of FIG. 4 andincorporating a FRM in an open state in accordance with an exemplaryembodiment of the invention;

FIG. 6 is a schematic illustration of a FRM in accordance with anotherexemplary embodiment of the invention, which may be used, for example,in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or theshunt of FIG. 3;

FIG. 7 is a schematic illustration of a FRM in accordance with anotherexemplary embodiment of the invention, which may be used, for example,in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or theshunt of FIG. 3;

FIG. 8 is a schematic illustration of a FRM in accordance with anotherexemplary embodiment of the invention, which may be used, for example,in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or theshunt of FIG. 3;

FIG. 9 is a schematic illustration of a FRM within a heart, inaccordance with another exemplary embodiment of the invention;

FIG. 10 is a schematic illustration of a FRM in accordance with anotherexemplary embodiment of the invention, which may be used, for example,in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or theshunt of FIG. 3;

FIG. 11 is a schematic illustration of a FRM in accordance with anotherexemplary embodiment of the invention, which may be used, for example,in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or theshunt of FIG. 3;

FIG. 12 is a schematic illustration of a FRM in accordance with anotherexemplary embodiment of the invention, which may be used, for example,in conjunction with the DPRD of FIG. 1, the shunt of FIGS. 2A-2B, or theshunt of FIG. 3;

FIG. 13A is a schematic illustration of an apparatus for remotelycontrolling a DPRD in accordance with some embodiments of the presentinvention;

FIGS. 13B-E are schematic illustrations of mechanisms for remotelycontrolling a DPRD, in accordance with some embodiments of the presentinvention; and

FIG. 14 is a flow chart illustrating a method of controlling pressure,for example, blood pressure in a heart, according to some embodiments ofthe present invention.

It will be appreciated that for simplicity and clarity of illustration,elements shown in the figures have not necessarily been drawn to scale.For example, the dimensions of some of the elements may be exaggeratedrelative to other elements for clarity. Further, where consideredappropriate, reference numerals may be repeated among the figures toindicate corresponding or analogous elements.

SUMMARY

The present invention may provide methods and devices for regulatingpressure in a body. According to some embodiments of the presentinvention, a differential pressure regulating device may include a shuntbeing positioned between two or more lumens in a body, to enable fluidsto flow between the lumens, and an adjustable flow regulation mechanismbeing configured to selectively cover an opening of the shunt, toregulate the flow of fluid through the shunt in relation to a pressuredifference between the body lumens.

According to some embodiments the pressure regulating device may includea shunt being positioned between two or more chambers in a heart, toenable fluids to flow between the chambers, an adjustable flowregulation mechanism being configured to selectively cover the openingof the shunt, to regulate the flow of fluid through the shunt, and acontrol mechanism to be coupled to the adjustable flow regulationmechanism, to remotely activate the adjustable flow regulationmechanism.

In another embodiment a method is provided to control in-vivo pressure,which may include implanting a differential pressure regulation devicein a body, the pressure regulation device including a shunt placedbetween two or more lumens in a body, deploying a flow regulationmechanism, and controlling the flow regulation mechanism settingaccording to changes in pressure differences between the lumens.

In a further embodiment of the present invention a method is provided tocontrol in-vivo pressure, which may include controlling a flowregulation mechanism flow setting using a control mechanism implanted ina body, the flow regulation mechanism being disposed within adifferential pressure regulation device that includes a shunt placedbetween two or more lumens, for example, between a left atrium of aheart and a right atrium of a heart.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those of ordinary skill in the artthat the present invention may be practiced without these specificdetails. In other instances, well-known methods, procedures, componentsand structures may not have been described in detail so as not toobscure the present invention.

It will be appreciated that although part of the discussion herein mayrelate, for exemplary purposes, to a heart, heart chambers and/or heartatriums, embodiments of the present invention are not limited in thisregard, and may be used in conjunction with various other vessels,lumens, organs or body sites. For example some embodiments of thepresent invention may include regulating fluid transfer between cavitiesin the brain, between selected organs, between blood vessels (e.g.,between the aorta and the vena-cava) etc., and/or between other suitablelumens, for example, zones, cavities, organs, vessels, regions or areasin a body.

Some embodiments of the present invention include, for example, a methodand apparatus for controlling in-vivo pressure by reducing or otherwisecontrolling pressure differences between two or more body sites, forexample, two chambers of the human heart (e.g., the left atrium and theright atrium). For example, such pressure control may be used to helpsolve the problem of increased cardiac filling pressure in patients withcongestive heart failure and predominantly diastolic dysfunction,thereby helping to minimize or prevent pulmonary fluid accumulation,edema formation and clinical complaint of dyspnea. In another examplethe pressure control may be used to reduce left ventricle fillingpressure. Some embodiments of the invention may include a DifferentialPressure Regulation Device (DPRD), for example, including a shunt, tubeor other structure having an orifice, tube or opening to fluidicallyconnect two or more lumens, for example, to connect a left atrium of aheart with a right atrium of the heart. In accordance with someembodiments of the invention, the DPRD may include an adjustmentmechanism or a regulation mechanism, able to adjust, modify or otherwiseregulate, for example the cross-sectional area of the orifice, forexample, in relation to a change in pressure difference between thefirst and second lumens, for example, such as to increase and/ordecrease the flow-rate of blood between the two lumens.

Some embodiments of the present invention may be used, for example, tounload an excessive filling pressure of a left heart ventricle in aCongestive Heart Failure (CHF) patient, and to potentially prevent orreduce the occurrence of pulmonary edema.

Some embodiments of the present invention include, for example,implanting an adjustable DPRD in a wall between two heart chambers,e.g., between the left atrium and the right atrium. The pressureregulation device may, for example, allow a selective volume of blood toflow from the left atrium to the right atrium, in relation to the changein pressure difference between the left atrium and the right atrium. Thepressure regulation device may, for example, be adjusted to selectivelychange the size or shape of the opening, amount of blood allowed to flowthrough, etc.

In some embodiments, the pressure regulation device may be configured tomaintain a continual flow between two or more lumens, for example,between the left atrium and the right atrium. For example, a shunt, tubeor other structure may be coupled to a cover, valve opening, valve stem,or other flow regulation mechanism that may be configured to becontinually ajar, to enable a selected minimal quantity of fluid tocontinually flow between two lumens in a body, for example, between theheart chambers. The cover may be subsequently adjusted, for example maybe further opened and/or closed, to control the quantity of fluid flowbetween the lumens. The fluid flow through the DPRD may increase ordecrease in accordance with changes in the pressure or pressuredifference between the two lumens. For example, cover may be openedand/or closed as the pressure in the left atrium increases or decreasesrelative to the pressure in the right atrium. In some embodiments theDPRD may be configured such that the orifice cover has no direct contactwith the shunt opening to reduce help minimize or prevent tissue growthon or around the orifice cover. Such a configuration may enable acontinuous fluid flow through the DPRD, and may help to prevent orreduce the occurrence of clotting or formation of biofilm or otherunwanted growths. In some embodiments the DPRD may be used to flush orclean out the shunt and/or shunt cover etc.

Reference is made to FIG. 1A, which schematically illustrates a DPRD 101implanted in a heart 109, in accordance with an exemplary embodiment ofthe present invention. DPRD 101 may be implanted between two or morebody lumens, for example, between a left atrium 102 and a right atrium103 of heart 102. DPRD 101 may be implanted in other heart chambers,using different arrangements of heart chambers, and/or in or betweenother body lumens. In some embodiments, an opening, puncture or otherstructure may be formed in a wall between two body lumens, for example,in septum 105 between left atrium 102 and right atrium 103, for example,using a puncturing or cutting device mounted to the distal end of acatheter or any other suitable puncturing mechanism. DPRD 101 may thenbe placed in a puncture using a catheter or another suitable deliverymechanism. In some embodiments, one or more tissue fixation elements,for example, support arms 106 may support DPRD 101 at a desired positionin a generated hole or puncture.

DPRD 101 may include, for example, an adjustable shunt, tube or pathway122 to enable fluids to flow between two body lumens, organs, regions orzones etc., for example between a left atrium 102 and a right atrium103. DPRD 101 may include a Flow Regulation Mechanism (FRM) 108 asdescribed herein, for example a flow valve, cover, valve opening, valvestem, or lid, to enable selected modification of the parameters of shunt122, for example, by changing the cross section of the opening of shunt122 or the shunt's shape etc., thereby regulating the blood flow fromleft atrium 102 to right atrium 103. In some embodiments FRM 108 may beset in a continually ajar position to enable a continual flow of bloodbetween the left atrium and the right atrium. For example, FRM 108 maybe purposefully left ajar, to enable a selected quantity of blood tocontinually flow between the heart chambers. FRM 108 may be subsequentlyadjusted, for example, by selectively changing the size or shape of theopening, amount of blood allowed to flow through, etc., to enable thearea around the opening of shunt 122 and FRM 108 to be limited and/orexpanded, thereby affecting effective flow-through of shunt 122, andenabling the quantity of blood flow between the chambers to becontrolled. DPRD 101 may include one or more control mechanisms 110, forexample, wires, springs, cords etc. to enable FRM 108 to be passivelyand/or actively controlled. In one embodiment springs may be used toenable FRM 108 to act in accordance with changes in differentialpressure, for example, by being pre-loaded with a selected tension, torespond in a controlled way to changes in one or more pressurethresholds.

FRM 108 may be configured to respond to selective pressure profiles,thereby providing a known pressure relief profile. For example, FRM 108may be preset, pre-calibrated and/or pre-configured to change itssetting, adjust its configuration or position, and/or change the orificewidth or flow amount etc., in accordance with changes in pressuredifference between the left and right atriums of the heart. FRM 108 maybe continually adjustable, for example to a continuously variablesetting, for example in response to environmental conditions and/orexternal controls. In at least these ways, DPRD 101 may provide aselected, predictable and/or guaranteed flow of fluid between two ormore bodily lumens or regions etc. In some embodiments the resting ordefault setting, opening size, flow level or position of FRM 108 may bechanged, for example, according to pre-programmed parameters and/orremote control mechanisms. In some embodiments a continuously open orajar FRM 108 may help prevent occlusion of shunt 122.

In some embodiments, below a certain pressure or pressure differential,the valve or device may be fully closed; however in other embodiments,below a certain pressure or pressure differential, the valve may be notfully closed or slightly ajar. For example, the valve may have a minimumopening size.

In some embodiments, one or more properties of the DPRD, for example,the size of the cross-section opening of the pressure regulation device,may be dependent on the blood pressure difference between the leftatrium and the right atrium. Therefore, in some embodiments, the bloodflow between the left atrium and the right atrium may be influenced bythe change in blood pressure difference between the left atrium and theright atrium.

A DPRD according to some embodiments of the invention may allow for areduction in ventricular pressure by reducing pressure in an atrium ofthe heart.

In some embodiments, a DPRD may be used for Atrium Septum Defect (ASD)patients, for example who may not be able to tolerate a completeuncontrolled atrium closure procedure, to selectively close a hole orgap in the septum.

In some embodiments, a DPRD may be used to transfer fluid from the leftatrium to the right atrium, for example, to aid a patient with pulmonaryhypertension. In such cases the DPRD may be positioned with FRM 108 inthe left atrium. According to some embodiments of the present invention,FRM 108 may be unidirectional or bi-directional.

In some embodiments, a plurality of DPRD's may be implanted in a wall orother structure, for example, to help provide redundancy, to implantdevices with different set ranges to achieve a higher level of openingcontrol, and/or to enable adding of additional devices. Implanting aplurality of DPRD's may enable the delivering catheter diameter to bereduced, as two or more DPRD's of a lesser diameter may be delivered.

In other embodiments FRM 108 may include a cover, lid or other suitablemechanism that may have various forms to enable partial or total closureof FRM 108. Reference is now made to FIGS. 1B-1G. In FIG. 1B FRM 108 mayinclude two or more arms 120 which may be configured to be continuouslyor constantly ajar at opening 125 of shunt 122. For example, FRM 108 maybe configured to remain continually at least partially detached fromshunt 122, to allow a continuous flow of fluid between left atrium 102and right atrium 103. Arms 120 may be further opened and/or closed inresponse to changes in pressure differences between the heart chambers.Arms 120 may be constructed from a flexible polymer or other suitablematerials. Arms 120 may have rounded shapes at arm ends 130, forexample, to help prevent blood stagnation.

In FIG. 1C FRM 108 may include a shunt 122, and two or more flexiblemembranes 135, which may be configured to be constantly ajar at opening125 to enable a continuous blood flow through shunt 122. For example, inthe various embodiments discussed herein, a device may be set so that nomatter what the pressure or pressure differential between chambers, aminimum opening size may be set or flow amount may occur. Membrane 135may include at least one spring-type mechanism, to help expand and/orcontract membrane 135, in response to changes in pressure differencesbetween the heart chambers.

In FIG. 1D FRM 108 may include a shunt 122, and one or more flexible orspring based lid, membrane or leaflets 150, optionally connected toshunt 122 by a spring or other suitable pressure sensitive mechanism155. In one embodiment pressure sensitive mechanism 155 may bepre-loaded to respond in a controlled way to changes in one or morepressure thresholds. Lid 150 may be configured to be constantly ajar atopening 125 to enable a continuous blood flow through shunt 122. FRM 108may include one or more raised areas 160, for example, thorn shapedobjects or objects with other suitable shapes to help prevent lid 150from making full contact with shunt 122.

In FIG. 1E FRM 108 may include a shunt 122, and one or more angledflexible membranes or leaflets 165, which may be configured to beconstantly ajar at opening 125 to enable a continuous blood flow throughshunt 122. In one embodiment leaflets 165 may be pre-loaded with aselected tension to respond in a controlled way to changes in one ormore pressure thresholds. Leaflet 165 may include at least one springmechanism or other suitable mechanism to help close and/or open leaflet165 in response to changes in pressure differences between the heartchambers. Leaflet 165 may include at least one magnet or electromagnet170 or other suitable mechanism to help remotely close and/or openleaflet 165. A conducting wire 172 or other suitable mechanism may beused to activate magnet(s) or electromagnet(s) 170.

In FIG. 1F FRM 108 may include a shunt 122, and a cap, valve opening,valve stem, or other mechanism 175, which may be configured to beconstantly ajar at opening 125 to enable a continuous blood flow throughshunt 122. Cap 175 may be coupled to a spring 177 or other suitablepressure sensitive mechanism. In one embodiment spring 177 may bepre-loaded with a selected tension to respond in a controlled way tochanges in one or more pressure thresholds. FRM 108 may include one ormore cap motion limiters 179. FRM 108 may include a fixed polarizedmagnet 181 and an electromagnetic coil 183 that includes one or moreconductors 185. Cap 175 may be opened and/or closed in response tochanges in pressure differences between the heart chambers and/or byremotely activating magnet 181 and/or magnetic coil 183. For example,when magnet 181 is activated cap 175 may be further opened, and whencoil 183 is activated cap 175 may be further closed.

As shown in FIG. 1G FRM 108 may include a shunt 122, and a cap 175,which may be configured to be constantly ajar at opening 125 to enable acontinuous blood flow through tube 122. Cap 175 may be connected toshunt 122 by a connection arm 185. Cap 175 may include cuts, slots,grooves or slits etc. 187 to enable a continuous blood flow throughshunt 122. Slots 187 may be of different sizes, depths, widths, ordensities, which may help dictate whether various areas of cap 175 areto be stronger and less flexible or weaker and more flexible, and maytherefore respond differently to changes in pressure differences betweenthe bodily lumens. For example, in an area where there are more ordeeper incursions the area may be relatively weak and flexible, therebyallowing cap 175 to be at least partially opened by a relatively lowpressure blood flow through shunt 122. In an area where there are fewerand/or more superficial incursions the area may be relatively strong orless flexible, thereby only allowing cap 175 to be at least partiallyopened by a relatively high pressure blood flow through shunt 122.

As shown in FIGS. 1H and 1I FRM 108 may include a shunt 122, and a cap175, which may be configured to be constantly ajar at opening 125 toenable a continuous blood flow through shunt 122. Cap 175 may be coupledto a spring 190 or other suitable pressure sensitive mechanism. Spring190 and cap 175 may be connected to a piston or pump mechanism 192. Ascan be seen in FIG. 1I, cap 175 may be opened and/or closed in responseto changes in pressure differences between the heart chambers and/or bypiston 192 activating spring 190 to extend and/or distend cap 175,thereby changing the size of opening(s) 125.

According to some embodiments of the present invention, the usage ofDPRD 101 may enable generation of a pressure curve related to therelationship between the change in pressure difference between twolumens, the flow through the flow control mechanism and the orificearea. Any required or selected design parameters may be used. Referenceis now made to FIG. 1J, which illustrates an example of such a pressurecurve. As can be seen in FIG. 1J, below a pressure differential of 12mmHg, the opening or orifice size may be relatively stable, and flow maybe influenced substantially by the pressure difference. When pressuredifference rises above approximately 12 mmHg until approximately 20 mmHgthe flow may increase at a higher rate, as it may now be influenced byboth the increase in orifice area and the increase in pressuredifference. When pressure difference rises above approximately 20 mmHgthe flow rate increase at a slower rate, since the orifice area may havealready reached its maximum cross-section, and the flow may beinfluenced substantially by the pressure difference. Pressuredifferences and/or may be effected by linear and/or non-linear changesin the orifice area. Other pressure difference, flow and/or orifice arealevels, relationships, and interrelationships may be used, as may otherparameters, variables, minimum and maximum limits etc.

Reference is made to FIGS. 2A and 2B, which schematically illustrate across-section view and a side view, respectively, of an adjustable DPRD201 in accordance with an exemplary embodiment of the invention. DPRD201 may include, for example, a frame 220 connected to one or moresupport arms, e.g., arms 211-216. Frame 220 may include, for example, aflexible fixation frame, ring or tube. Frame 220 may be formed from aflexible material, for example, a flexible metal, super elastic alloy,and/or a shape-memory material, e.g., Nitinol or other suitablematerials.

Although DPRD 201 is described herein as having six arms or appendages211-216, for exemplary purposes, embodiments of the present inventionare not limited in this regard and may include a different number ofarms, for example, one arm, two arms, ten arms, or the like.

Arms or appendages 211-216 may be flexible and/or may be pre-shaped toachieve a desired functionality. For example, arms 211-216 may be foldedduring an insertion process, e.g., inside a suitable delivery tube. Insome embodiments, arms 211-216 may be formed of a super elasticmaterial, for example, a Shape-Memory Alloy (SMA), e.g., nickel-titanium(NiTi) alloy. Other suitable materials may include, for example, metals,stainless steel, and/or other suitable materials. At least part of arms211-216 or other selected elements of DPRD 201 may be coated and/ortextured to increase their bio-compatibility and/or to increase thedegree to which these elements may become selectively endothelialized,as may be desired in some implantation conditions.

DPRD 201 may include, for example, a FRM 250, for example, including acover, valve opening, valve stem, or other flow regulation mechanismwith one or more pre-set positions, to selectively cover an orificeresulting from the deployment of DPRD 201. FRM is described in detailbelow.

As illustrated schematically in FIG. 2B, DPRD 201 may have two sides,which may be referred to herein as a proximal side 251 and a distal side252, respectively. For example, DPRD 201 may be implanted in heart 109,such that the proximal side 251 of DPRD 201 may face the right atrium103, and the distal side 252 of DPRD 201 may face the left atrium 102.Other orientations of sides 251 and 252 may be used, as may othernumbers of sides.

In some embodiments, the distal side 252 of DPRD 201 may be connected toa distal set of arms or appendages, e.g., arms 211-213, and the proximalside 251 of DPRD 201 may be connected to a proximal set of arms orappendages, e.g., arms 214-216. Thus, when DPRD 201 is implanted inheart 109, the distal set of arms 211-213 may first be discharged in theleft atrium 102, e.g., to the right of septum 105 in FIG. 1, thussupporting DPRD 201 to the left side, from the patient's perspective, ofseptum 105. Then, as the insertion of DPRD 201 is completed, e.g., byretracting a catheter or delivery tube carrying DPRD 201, the proximalset of arms 214-216 may be discharged in the right atrium 103, e.g., tothe left of septum 105 in FIG. 1, thus supporting the right side, fromthe patient's perspective, of septum 105. In this manner, arms 211-216may support frame 220 of DPRD 201 at a desired position between the leftatrium 102 and the right atrium 103.

Reference is now made to FIG. 3, which schematically illustrates a DPRD301 in accordance with another exemplary embodiment of the presentinvention. DPRD 301 may include, for example, a frame 302 connected toone or more arms or appendages, for example, arms 303 and 304.

Frame 302 may include, for example, a flexible fixation frame formedfrom a flexible material, for example, a flexible metal, e.g., Nitinolor Nitinol wire. Frame 302 may have a generally helical shape, forexample, as schematically illustrated in FIG. 3, and may be integrallyformed with curved arms 303 and 304 at either end of frame 302, asschematically illustrated in FIG. 3. Other suitable shapes may be used.Arms 303 and 304 may be flexible and may be pre-shaped to achieve adesired functionality. For example, arms 303 and 304 may be foldedduring an insertion process, e.g., inside a suitable delivery tube, inorder to be subsequently discharged for positioning the frame 302 in apuncture. In accordance with some exemplary embodiments of the presentinvention, DPRD 301 may include a FRM 350, for example, a FRM asdetailed herein.

Reference is also made to FIG. 4, which schematically illustrates a DPRD401 including a DPRD 450 in accordance with an exemplary embodiment ofthe invention. DPRD 450 may be an example of FRM 250 or FRM 350. Forexemplary purposes only, DPRD 450 is shown in conjunction with a DPRD401 which may be similar to DPRD 201, although DPRD 450 may be used inconjunction with DPRD 301 or any other suitable shunts or medicaldevices.

DPRD 450 may include, for example, a disk 432 connected to a ring 431 bya spring 433. Disk 432 may be formed of a bio-compatible material, forexample, pyrolitic carbon or stainless steel. Spring 433 may include oneor more swivel springs, twisting springs, or any other spring elements,which may hold disk 432 inside ring 431 when there is substantially nopressure differential between the two sides of DPRD 401, e.g., betweenthe proximal side 251 and the distal side 252 of DPRD 201 of FIG. 2B.

In response to a pressure differential between the two sides of DPRD401, disk 432 may move away from the atrium having the relatively higherpressure, typically the left atrium, bending spring 433 which may applya counterforce to the movement of disk 432, thereby opening and/orenlarging a cavity through which blood may pass. The counterforceapplied by spring 433 may depend on the pressure differential betweenthe two sides of DPRD 401, for example when the pressure in an atriumforces spring 433 to contract, such that the higher the pressuredifferential across DPRD 401, the larger the opening to allow relief ofsuch pressure differential by flow from the high pressure side to thelow pressure side. In this manner, the pressure differential between theproximal and distal sides of DPRD 401 may be controlled in accordancewith one or more selected levels. In some embodiments the variousconfigurations for DPRDs described herein may allow for opening sizes orflow rates that vary continuously with pressure differentials.

It will be appreciated that when there is substantially no pressuredifference between the two sides of DPRD 401, or when the pressuredifference is relatively small, disk 432 may be fully closed, or inaddition may not entirely block the flow of blood through DPRD 450, forexample, through the area between disk 432 and ring 431. For example,disk 432 may be selectively set with a gap between ring 431 and disk432, such that disk 432 may function as a leaking valve to enable bloodto continuously flow through a puncture. The continual freedom of flowacross DPRD 401 may, for example, prevent blood clotting and/or thrombusformation in and/or around disk 432.

In some embodiments, ring 432 may be asymmetric, for example, ring 432may have a relatively wider upper section 451 and a relatively narrowerlower section 452. This may allow, for example, blood passage at arelatively small flow-rate during tilting of disk 432 under increasedpressure, until disk 432 bends beyond the upper section of ring 431,thereby providing a pressure or pressure differential threshold at whichthe valve opens or begins to open, to increase the blood flowcross-section through the vessel. The pressure threshold may be acontinual (e.g., infinitely variable) set of pressure points at whichthe valve opens or allows a pressure flow in accordance with thepressure. For example, the valve may remain closed or slightly ajaruntil a certain pressure, then above that pressure open continuallyuntil an upper pressure is reached, at which the valve is fully open. Itis noted that an asymmetric ring 432 or other asymmetric components maybe used to achieve similar functionality in various other FRMs, DPRDs,shunts and/or devices in accordance with embodiments of the presentinvention.

In some embodiments, ring 431 may be formed of, for example, a suitablemetal. In some embodiments, ring 431 may be integrated within frame 220,or ring 431 and frame 220 may be implemented using an integratedring-frame component. Ring 431 and/or frame 220 may be formed of asuitable wire or tube. Ring 431 and/or arms 211-216 may be formed of asuitable wire or tube, e.g., the same wire or tube and/or the samematerial.

Reference is also made to FIG. 5, which schematically illustrates DPRD401 implanted in heart 109, incorporating DPRD 450 in an open state inaccordance with an exemplary embodiment of the present invention. Apressure difference may exist between left atrium 102 and right atrium103, for example, the pressure in left atrium 102 may be larger than thepressure in right atrium 103. The pressure difference may cause disk 432to move towards right atrium 103 and bend the spring 433, therebycreating an enlarged opening through which more blood may flow from leftatrium 102 to right atrium 103. As the blood flows towards right atrium103, the pressure in left atrium 102 may decrease and the pressure inthe right atrium may increase, thereby reducing the pressure differencebetween the left atrium 102 and the right atrium 103, and allowingspring 433 to pull back disk 432 towards a closed or substantiallyclosed position. Other mechanisms to enable disk 432 to move may beused.

FIG. 6 schematically illustrates a DPRD 650 in accordance with anotherexemplary embodiment of the invention. DPRD 650 may be an example of FRM108, FRM 250 or FRM 350. DPRD 650 may include, for example, ring 431 anda pre-shaped wire 634. Wire 634 may include a flexible metal wire, forexample, formed of Nitinol or other suitable materials. In oneembodiment wire 634 may be curved to a shape of a horse-shoe or tongueor another suitable shape. In some embodiments, an end of wire 634 maybe attached to ring 431, or wire 634 and ring 431 may be formed of thesame wire, tube or other suitable material.

Wire 634 may be covered by or connected to a cover or sheet 635, whichmay include, for example, a flat sheet of bio-compatible material, forexample, a biological tissue material used in conjunction withartificial valve leaflets. Sheet 635 may be attached to wire 634, forexample, using one or more stitches 636.

DPRD 650 may be included in, for example, DPRD 201 or DPRD 301,implanted in heart 109. A pressure difference may exist between leftatrium 102 and right atrium 103, for example, the pressure in leftatrium 102 may be larger than the pressure in right atrium 103. Thepressure difference may cause sheet 635 to move, utilizing theelasticity of wire 634, thereby creating a cavity through which bloodmay flow from left atrium 102 to right atrium 103. As the blood flows inthat direction, the pressure in left atrium 102 may decrease and thepressure in the right atrium may increase, thereby reducing the pressuredifference between the left atrium 102 and the right atrium 103, andallowing sheet 635 to move back towards a closed or substantially closedposition or towards a position wherein sheet 635 is in a marginallyopened position.

It is noted that when there is no pressure difference between the leftatrium 102 and the right atrium 103, or when the pressure difference isrelatively small, sheet 635 may not entirely block a blood flow throughDPRD 650, for example, through the area around sheet 635, or betweensheet 635 and ring 431. This may, for example, prevent blood clottingand/or thrombus formation in and/or around sheet 635 or DPRD 650.However, as with the other configurations discussed herein, in otherembodiments, the opening or valve may be completely closed at certainpressure differentials.

FIG. 7 schematically illustrates a FRM 750 in accordance with anotherexemplary embodiment of the invention. FRM 750 may include, for example,ring 431 connected to a cone 737 using one or more springs 738. Cone 737may be positioned inside ring 431, and may be formed of, for example, abio-compatible material, e.g., pyrolitic carbon or stainless steel. Cone737 may have a suitable shape, for example, rectangular, square-shaped,circular, oval, trapezoid-shaped, cone-shaped, or other suitable shapes.

FRM 750 may be included in a shunt, e.g., DPRD 201 or DPRD 301,implanted in heart 109. Springs 738 may include one or more compressionsprings, and may hold cone 737 inside ring 431, for example, whensubstantially no pressure difference exists between left atrium 102 andright atrium 103.

When a pressure difference exists between left atrium 102 and rightatrium 103, for example, when the pressure in left atrium 102 is largerthan the pressure in right atrium 103, FRM 750 may allow blood flow fromleft atrium 102 to right atrium 103. The pressure difference may causecone 737 to move back against springs 738, thereby opening or enlarginga cavity through which blood may flow from left atrium 102 to rightatrium 103. As the blood flows in that direction, the pressure in leftatrium 102 may decrease and the pressure in the right atrium mayincrease, thereby reducing the pressure difference between the leftatrium 102 and the right atrium 103, and allowing cone 737 to move backtowards a closed or substantially closed position.

It is noted that when there is no pressure difference between the leftatrium 102 and the right atrium 103, or when the pressure difference isrelatively small, cone 737 may not entirely block a blood flow throughFRM 750, for example, through the area around cone 737, or between cone737 and ring 431. This may, for example, prevent blood clotting and/orthrombus formation in and/or around cone 737 or FRM 750.

FIG. 8 schematically illustrates a FRM 850 in accordance with anotherexemplary embodiment of the invention. FRM 850 may include, for example,a flexible valve 839 connected to and positioned inside ring 431. Valve839 may be formed of, for example, a bio-compatible material, e.g.,polyurethane or silicone. Valve 839 may be attached to ring 431, forexample, by gluing or stitching a base 840 of valve 839 inside ring 431.Valve 839 may include one or more leaflets, for example, leaflets 841and 842 able to move and create or enlarge an opening 843. In someembodiments, the size of opening 843 may be in relation to a pressureapplied to leaflets 841 and 842.

FRM 850 may be included in a shunt, tube or conduit, e.g., DPRD 201 orDPRD 301, implanted in heart 109. When a pressure difference existsbetween left atrium 102 and right atrium 103, for example, when thepressure in left atrium 102 is larger than the pressure in right atrium103, FRM 850 may allow blood flow from left atrium 102 to right atrium103. The pressure difference may stretch, spread or push leaflets 841and/or 842, thereby increasing the distance between them and enlargingthe opening 843, through which blood may flow from left atrium 102 toright atrium 103. As the blood flows in that direction, the pressure inleft atrium 102 may decrease and the pressure in the right atrium mayincrease, thereby reducing the pressure difference between the leftatrium 102 and the right atrium 103, and allowing leaflets 841 and/or843 to move back towards a closed or substantially closed position.

It is noted that when there is no pressure difference between the leftatrium 102 and the right atrium 103, or when the pressure difference isrelatively small, valve 839 and leaflets 841 and 842 may not entirelyblock a blood flow through FRM 850, for example, through the opening843. This may, for example, prevent blood clotting and/or thrombusformation in and/or around valve 839 or FRM 850.

FIG. 9 schematically illustrates a DPRD 950 within heart 109, inaccordance with another exemplary embodiment of the invention. DPRD 950may include a plurality of balloons or sacs inter-connected through oneor more tubes, for example, a non-compliant balloon 943 connectedthrough a tube 944 to a compliant balloon 945. The non-compliant balloon943 may be placed in the left atrium 102 and/or in a puncture, and thecompliant balloon 945 may be placed in the right atrium 103. In someembodiments, balloons 943 and/or 945 may be may be attached to a ring(e.g., ring 431). In some embodiments balloons 943 and/or 945 maycontain a liquid 920.

Liquid 920 may flow from balloon 943 to balloon 945 or vice versa, forexample, in relation to a pressure difference between the left atrium102 and the right atrium 103. For example, when there is a relativelylarger pressure in the left atrium 102, liquid 920 may flow fromnon-compliant balloon 943 through tube 944 to compliant balloon 945,thereby deflating the non-compliant balloon 943 and inflating thecompliant balloon 945. It is noted that compliant balloon 945 may bemore flexible than non-compliant balloon 943, allowing the compliantballoon 945 to act as a spring mechanism to control the deflating of thenon-compliant balloon 943.

FIG. 10 schematically illustrates a DPRD 1050 in accordance with anotherexemplary embodiment of the invention. DPRD 1050 may include, forexample, ring 431 and a flexible disk 1046 having a hole 1047. In someembodiments, hole 1047 may be substantially circular and may be located,for example, substantially in the center of flexible disk 1046. Flexibledisk 1046 may be formed of, for example, a flexible polymetric material,e.g., silicone rubber or polyurethane.

DPRD 1050 may be implanted in heart 109, and hole 1047 may change itsdiameter in relation to a pressure difference between the left atrium102 and the right atrium 103. For example, the pressure difference maypush backwards or stretch the flexible disk 1046, thereby enlarging thehole 1047 and allowing a larger area through which blood may flow fromthe left atrium 102 to the right atrium 103.

It is noted that when there is no pressure difference between the leftatrium 102 and the right atrium 103, or when the pressure difference isrelatively small, hole 1047 may still be open and may have a relativelysmall diameter, and flexible disk 1046 may not entirely block a bloodflow through DPRD 1050. This may, for example, prevent blood clottingand/or thrombus formation in and/or around DPRD 1050.

FIG. 11 schematically illustrates a DPRD 1150 in accordance with anotherexemplary embodiment of the invention. DPRD 1150 may include, forexample a balloon or sac 1148 such as a non-compliant balloon containinga liquid 1120. The balloon 1148 may be placed or connected inside a ring1131, which may include, for example, a ring similar to ring 431 and/ora frame. A tube 1149 may connect balloon 1148 to a reservoir 1155, whichmay include one or more pistons 1151 able to move against one or morecompression springs 1152. Springs 1152 may be formed of, for example,metal or a suitable elastic material.

DPRD 1150 may be implanted in heart 109, and balloon 1148 may change itsvolume in relation to a pressure difference between the left atrium 102and the right atrium 103. For example, the pressure difference may pushor deflate the balloon 1148, thereby causing liquid 1120 to flow fromballoon 1148 to reservoir 1155. This may create or enlarge an openinginside ring 1131, through which blood may flow from the left atrium 102to the right atrium 103.

FIG. 12 schematically illustrates a DPRD 1250 in accordance with anotherexemplary embodiment of the invention. DPRD 1250 may include, forexample a balloon 1148 such as a non-compliant balloon containing aliquid 1120. The balloon 1148 may be placed or connected inside a ring1131, which may include, for example, a ring similar to ring 431 and/ora frame. A tube 1149 may connect balloon 1148 to a reservoir 1155, whichmay include one or more pistons 1151 able to move. The piston 1151 maybe moved, for example, using a motor 1153, which may include an electricmotor, e.g., a step motor or other suitable motors. Motor 1153 may move,push or pull pistons 1151, thereby causing liquid 1120 to flow fromballoon 1148 to reservoir 1155 or vice versa. This may change the volumeof balloon 1148, thereby increasing or decreasing a size of an openinginside ring 1131, through which blood may flow from the left atrium 102to the right atrium 103.

According to some embodiments of the present invention, the DPRD may beactively controlled, for example, by a patient or medical serviceprovider. In one embodiment DPRD may be operated using external and/ormanually provided instructions. For example, motor 1153 may operate inaccordance with external and/or manually provided instructions.Additionally or alternatively, motor 1153 may operate in relation to apressure difference between the left atrium 102 and the right atrium103. For example, a pressure-dependent close loop 1260 may be used,incorporating one or more pressure transducers 1254. The pressuretransducers 1254 may measure an absolute pressure in one or more heartchambers, for example, in left atrium 102 and/or right atrium 103, ormay measure a differential pressure between two heart chambers, forexample, between left atrium 102 and right atrium 103. Based upon thepressure information, motor 1153 may operate and move, push or pull thepistons 1151.

In other embodiments DPRD may be remotely operated using one or more ofelectric mechanisms, mechanical mechanisms, wireless mechanisms,pneumatic mechanisms or other suitable mechanisms. For example, a wire,line, spring, pin, cable, hook, latch, motor or magnet may be connectedto the DPRD to enable the DPRD to be remotely controlled by a patientand/or medical service provider. As can be seen with reference to FIG.13A at least one line or control lead 1320 may connect DPRD 1300 to acontrol mechanism 1310, for example, a control box. For example, controllead 1320 may exit vein 1330 through a puncture or hole 1335. Controlmechanism 1310 may include, for example, a mechanical interface,electrical interface, pull/push wire, spring, magnet or other suitableelements or mechanisms to enable DPRD 1300 to be remotely controlled.

Control mechanism 1310 may be a micro mechanism that may be placedinternally or externally, for example, it may be sown into tissue undera patient's skin, to provide external access for a medical serviceprovider, or it may be placed internally in proximity to a location thatmay be accessed by a medical service provider with a minimally invasivetechnique.

In one embodiment DPRD 1300 may be controlled wirelessly from anexternal ‘transmitting’ unit. For example, control signals may bedelivered from outside a patient's body using telemetry, localized RFradiation, localized Ultrasound radiation, external magnetic field,localized heating and other suitable means of generating signals. Insuch an embodiment DPRD 1300 may include a ‘receiving’ unit. Thereceiving unit may include an internal power source (e.g., a battery),or may receive its energizing power from the control signal or othertransmitted signals. The receiving unit may be coupled to an externalpower source, for example, via an implanted plug, or may be directlyconnected to DPRD 1300 on a temporary basis (e.g., at the doctor'soffice), were the implanted plug may relay command signals and/or powerto activate DPRD 1300.

Reference is now made to FIG. 13B, which indicates an example of acontrol mechanism 1310 being positioned under the skin surface 1360. Inone example control lead 1320 may be accessed by entering the patientusing a conventional needle or syringe 1365, for example by making asmall incision. Control lead(s) 1320 may be controlled externally orinternally to enable DPRD 1300 to be controlled. In some embodimentscontrol lead(s) 1320 may operate within a tube, for example a siliconpressurized tube 1370. Control mechanism 1310 may include a remote valveopening/closing mechanism, for example, to enable monitoring of heartpressure, monitoring of DPRD functioning etc. In one example, controlmechanism 1310 may be used to monitor blood flow changes in response tovalve positioning. Control mechanism 1310 may enable manual reduction ofheart pressure or in blood pressure in certain chambers or the heart inthe case of clinical need. Control mechanism 1310 may enable flushing orcleaning of DPRD 1300 at selected intervals, for example, by increasinginternal blood pressure or fluid pressure. In other embodiments flushingor cleaning may be enabled using a flushing or cleaning fluid, forexample, saline solution that may be entered into control lead 1320 at aselected pressure to cause the orifice to be cleaned or flushed. Suchcleaning may help in reducing undesired growth, infections etc.associated with DPRD 1300.

Control mechanism 1310 may be coated with one or more substances toprevent thrombosis or other conditions. DPRD 1300 may include spikes,thorns or other suitable mechanisms to prevent a FRM from being in fullcontact with a shunt, or to ensure only minimal contact between a FRMand a shunt. Control mechanism 1310 may enable parts of DPRD 1300 to beremotely replaced, cleaned, serviced or otherwise manipulated. Controlmechanism 1310 may enable a pre-configured or designed leak to beremotely opened, closed, or otherwise changed in accordance withclinical requirements. Control mechanism 1310 may enable blocking up ofthe DPRD's orifice or cavity, for example, by remotely placing a plug inthe orifice to cease functioning of the DPRD. One or more of the abovequalities may enable a health service provider to remotely control thefunctioning of DPRD 1300.

In one embodiment, as can be seen with reference to FIG. 13C, controlmechanism 1310 may include one or more push knobs 1340 or other suitablecontrols or mechanisms that may be controlled using a finger or othersuitable implement. For example, the various push knobs 1340 may bepushed individually, simultaneously and/or in various other combinationsto achieve a desired effect in DPRD 1300. In one embodiment controlmechanism 1310 may include, for example, one or more rods or electricconductors 1350 to help control DPRD 1300. In one embodiment controlmechanism 1310 may include, for example, one or more security mechanisms1345, for example, a locking button to help prevent non-required changesfrom being made to the operation of DPRD 1300. In other embodimentscontrol mechanism 1310 may include one or more springs or other suitablecontrol mechanisms coupled to rod 1350 and DPRD 1300.

In one embodiment, as can be seen with reference to FIG. 13D, controlmechanism 1310 may be used to control DPRD 1300, for example using oneor more rods or wires 1375 etc., optionally operating within tube 1370.DPRD 1300 may include a cover 1377, for example, flexible ornon-flexible cover, which may be left constantly ajar, for example, toform gap 1379. In one embodiment cover 1377 may be constructed from arigid material and may be assembled or connected in a rigid manner to alocking mechanism 1380. Once cover 1377 has been set in a selectedposition by locking mechanism 1380, it may remain stable, for example,not being affected by blood pressure changes, until cover 1377 isre-positioned. In such a case, cover 1377 may only be adjusted byintentional and controlled actions using control mechanism 1310, forexample, wires 1375 using signals, or other suitable communicationlinks.

Locking mechanism 1380 may enable cover 1377 to be remotely set in oneor more positions. Locking mechanism 1380 may include, for example, oneor more of a spring, latch, lever, notch, slot, hook, slide or othersuitable locking mechanism(s). For example, position # 1 may be a lowerposition, for example where the hook 1325 fastens onto the catchingmechanism 1332 as indicated; position # 2 may be a medium position, forexample where the hook 1325 fastens onto the catching mechanism 1333;position # 3 may be a higher position for example where the hook 1325fastens onto the catching mechanism 1334. Other settings, opening sizes,flow levels, positions and numbers of positions may be used. Controlmechanism 1310 may include security features, for example, to helpprevent unauthorized personnel from activating DPRD 1300 (e.g., specialtools and magnets, coded sequence, password etc).

In one embodiment, as can be seen with reference to FIG. 13E, controlmechanism 1310 may be used to control DPRD 1300, for example using anauxiliary hydraulic system. DPRD 1300 may be connected to the hydraulicsystem, for example, via one or more tubes 1390 that may help controlthe pressures and/or flow rates of fluids delivered through DPRD 1390.DPRD 1390 may be connected to the hydraulic system when required, or maybe permanently attached to the hydraulic system. In one embodimenttubing 1390 may increase the fluid pressure in DPRD 1300, for example,to provide significant force on or inside the shunt. Tubing 1390 mayadditionally or alternatively be used for “maintenance”, for example, byforcing liquid through the shunt, for example, via shunt base 1392, toflush, clean and/or lubricate the shunt and/or FRM 1396, and/or torelease moving parts in DPRD 1300 in order to keep DPRD 1300 in arequired operating condition or state. In one example, a substance(e.g., saline solution) may be injected and/or extracted to/from tubing1390 to change the pressure at base 1392 and thereby activate pistondiaphragm 1394. Piston diaphragm 1394 may be extended and/or distendedthereby causing FRM 1396 to be manipulated, for example, to open and/orclose FRM 1396, to allow fluid to selectively flow through DPRD 1300.Tube 1390 may be connectable to tube 1320 (see FIGS. 13A and 13B) and/orto a needle 1366 or other suitable device for penetrating a patient'sskin to connect to tube 1390. In one embodiment the hydraulic mechanismmay be used after deployment of DPRD 1300 in the body, for example toverify operability of DPRD 1300. In a further embodiment the hydraulicmechanism may be used when checking DPRG operability followingdeployment of DPRD 1300 in the body.

It will be appreciated that some embodiments of the present inventionmay use one or more threshold values, pre-defined parameters, conditionsand/or criteria, for example, to trigger an activation or ade-activation of a shunt, a DPRD or a FRM.

Various suitable techniques for implanting a device according to anembodiment of the invention may be used. According to some embodiments,the pressure regulation device may be delivered and implanted in apatient's body using a minimally invasive procedure, for example, usingpercutaneous delivery. In such an example, the device may be mounted ona catheter delivery system and inserted to the body via small incision.Once the device is in the correct location inside the body, it may bedeployed by an operator, expanded and locked in place. A device that isdelivered on a catheter may be, for example, contracted or folded into asmall dimension, and the device may self-expand upon deployment. Inother embodiments the pressure regulation may be delivered usinginvasive surgery, for example where a surgeon makes a larger opening inthe body in order to achieve more direct contact with the deviceimplantation location.

In one embodiment of the present invention, as described in embodimentsin U.S. patent application Ser. No. 09/839,643, entitled “METHOD ANDAPPARATUS FOR REDUCING LOCALIZED CIRCULATORY SYSTEM PRESSURE” and filedon 20 Apr. 2001, in particular in FIGS. 3-5, a transseptal needle setmay be advanced toward the wall of the right atrial septum. Access maybe made from the femoral vein with the apparatus being advanced throughthe inferior vena cava and into the right atrium. Once transseptalpuncture has been achieved, a guidewire may be exchanged for a needlecomponent and then passed into the left atrium. The process of securingcatheter access to the left atrium by way of a transseptal puncture isknown in the art. After a transseptal sheath is positioned in the leftatrium, as described above, the placement of a shunt made in accordancewith embodiments of the present invention may be initiated.

The dilator and wire may subsequently be withdrawn from the sheath thatmay now extend from the femoral vein access point in the patient's grointo the left atrium, traversing the femoral vein, the illiac vein, theinferior vena cava, the right atrium, and the atrial septum etc. Thedelivery catheter may be passed through the sheath while underfluoroscopic visualization. Radiopaque markers may be provided on thiscatheter as well as the sheath in order to locate specific points. Thedelivery catheter may be carefully and slowly advanced so that the mostdistal portion of the left-atrial fixation element is emitted from thedistal opening of the catheter and into the chamber of the left atrium.The fixation elements may be formed from a spring-like material and/ormay be a super-elastic of shape-memory alloy, so that as it leaves theconstraint provided by the inner area of the delivery catheter, itreforms into its pre-configured fully formed shape. The assembly of thesheath and the delivery catheter may then slowly be retracted en bloc soas to withdraw the fixation elements towards the atrial septum. Thephysician may stop this retraction when it becomes apparent byfluoroscopic visualization as well as by tactile feedback that thefixation element has become seated against the atrial septum. At thatpoint, the sheath alone may be retracted, uncovering the shunt andpositioning it within the opening that has been created within theatrial septum. The sheath may then be further retracted, allowing theright-atrial fixation element to reform into its fully formed shape. Theentire shunt assembly or DPRD may then be detached from the deliverycatheter system. The DPRD may be controlled within the delivery catheterby means of long controller wire that has independent translationalcontrol within the catheter area. This attachment may be formed by anyconventional method, e.g., a solder or adhesive or the like that maymechanically detach at a prescribed tension level, that level beingexceeded by the physician at this point in the procedure by firmlyretracting the controller wire. Other methods of deployment of DPRDand/or FRM may be used.

Reference is now made to FIG. 14, which illustrates a method ofdelivering a DPRD and/or a FRM into a body area, for example, the septumof the heart between the left and right atrium, according to someembodiments of the present invention. Implantation of a device in theseptum may involve one or more of the following processes: a)identifying the precise site for implantation; b) aiming the devicetoward the selected site; and c) ensuring accuracy and integrity of theimplantation. The ideal implantation position may be chosen, forexample, by a medical professional, for example, by imaging the septumand analyzing the septum anatomy (e.g., by TEE). The aiming may includeidentifying the precise device delivery tool location using known toolsfor ‘mapping’ the septum site. Markers may be added to the deliverytools and devices (e.g., gold markers). Once the position has beenidentified and the device has been deployed, the medical professionalmay check and test the device installation, optionally before fullretrieval of the delivery system. For example, the medical professionalmay use direct contact such as physically challenging or pulling theentire device (e.g., by pulling gently on the device to ensure properanchoring). The anchoring may be tested by non-contact means (e.g.,using electromagnetic imaging, Echo, x-ray, angiography with contrastmaterial etc.).

At block 140 a DPRD may be implanted between two or more chambers,lumens, organs, regions, zones etc. in a body, for example, using acatheter. At block 141 a FRM may be deployed in a selected setting orposition, for example, to enable a continuous flow of fluid between twoor more lumens, and to be selectively activated or de-activated inaccordance with changes in pressure differences between the lumens. Atblock 142 the FRM may be controlled (e.g., passively) in response tochanges in pressure differences between the lumens, for example, FRM maybe further opened and/or closed in response to a pressure change.Optionally, at block 143 the DPRD and/or FRM may be remotely controlledto help control the flow of fluids between the lumens. In someembodiments the remote control of the DPRD and/or FRM may enablecleaning the DPRD and/or FRM, disabling the DPRD and/or FRM, changingelements of the DPRD and/or FRM etc. Any combination of the above stepsmay be implemented. Further, other steps or series of steps may be used.

The foregoing description of the embodiments of the invention has beenpresented for the purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed. It should be appreciated by persons skilled in the art thatmany modifications, variations, substitutions, changes, and equivalentsare possible in light of the above teaching. It is, therefore, to beunderstood that the appended claims are intended to cover all suchmodifications and changes as fall within the true spirit of theinvention.

1. A device for reducing elevated left atrial pressure, the devicecomprising: a shunt element configured to define a passageway betweenthe left atrium and right atrium through the atrial septum; and asupport structure configured to support the shunt element in a holethrough the atrial septum, wherein the device is contractable forpercutaneous delivery and self-expandable upon deployment in the holethrough the atrial septum.
 2. The device of claim 1, wherein said shuntelement comprises a valve element configured to regulate blood flowbetween the left atrium and the right atrium through the shunt element.3. The device of claim 2, wherein said shunt element allows flow fromthe left atrium to the right atrium responsive to a pressuredifferential between the left atrium and the right atrium.
 4. The deviceof claim 2, wherein the valve element comprises a leaflet.
 5. The deviceof claim 2, wherein the valve element comprises a plurality of leaflets.6. The device of claim 2, wherein the valve element comprises a duckbillvalve.
 7. The device of claim 2, wherein the valve element is coupled tothe support structure by stitching.
 8. The device of claim 1, whereinthe shunt element is cylindrical.
 9. The device of claim 1, wherein thesupport structure comprises a plurality of flanges.
 10. The device ofclaim 1, wherein the support structure comprises first and secondflanges.
 11. The device of claim 10, wherein the first and secondflanges are annular.
 12. The device of claim 10, wherein the first andsecond flanges are configured to respectively engage first and secondsides of the atrial septum when deployed.
 13. The device of claim 12,wherein at least one of the first and second flanges comprises a curvedportion that does not contact the atrial septum when deployed.
 14. Thedevice of claim 12, wherein at least one of the first and second flangescomprises a straight portion that is parallel to and in contact with theatrial septum when deployed.
 15. The device of claim 10, wherein thefirst and second flanges are substantially the same size as one another.16. The device of claim 1, further comprising a catheter forpercutaneously delivering the device in the hole through the atrialseptum.